Project Summary/Abstract With lack of effective treatment for Alzheimer?s disease (AD), it is critical to identify modifiable preventive measures such as diet that can prolong healthy aging and reduce risk of AD, especially in the middle-age, which might be a potentially critical window for successful intervention. Our previous work from the longitudinal Washington Heights, Hamilton Heights, and Inwood Columbia Aging Project (WHICAP) has indicated that adherence to either a Mediterranean-type diet or other healthy diets was related to decreased risk for AD and better brain and cognitive measures in elderly subjects. Based on the recently funded OFFSPRING study, the proposed study is an important extension of our efforts to understand whether diet is related with brain and cognitive health in middle-aged offspring of the multi-ethnic WHICAP participants. As it is believed that AD pathology begins in the brain in the 5th or 6th decades of life, identifying factors that can prevent the earliest decline in brain or cognition in these life periods will be extremely important towards a successful prevention of AD in late life. Furthermore, Hispanics and African-Americans have two to three times higher rates of AD than non-Hispanic Whites, and such racial disparities appears to be more prominent in mid-life. While many environmental- and individual-level adverse factors, including socioeconomic status and psychosocial factors, account for a substantial proportion of the racial disparities in cognitive performance, there remain unexplained race-related variations in cognition. Diet may represent a key modifiable lifestyle factor that additionally explains this racial disparity. Identifying and evaluating potential protective dietary factors for AD among middle-aged multiethnic populations will help to clarify potential modifiers for disparities in cognitive impairment and lay a solid foundation for prioritizing public health efforts. The overall aim of this study is to examine whether diet is related with sensitive brain and cognitive measures among 3,000 middle- aged offspring of a multiethnic group of parents. Specifically, the project will: 1) Examine whether dietary patterns are related to cognitive measures in middle-aged adults; investigate whether above associations differ among Hispanics, African-Americans, and non-Hispanic Whites; 2) Examine whether diet is related to multimodal neuroimaging measures; investigate whether the associations between diet and brain imaging biomarkers (neurodegeneration, cerebrovascular events, brain connectivity, neuropathology, and a Neuroimaging index) differ among Hispanics, African-Americans, and non-Hispanic Whites; 3) Examine whether early-life dietary exposure (indirectly estimated by offspring parents? diets or directly recalled) is related to mid-life brain and cognitive health. Overall, successful completion of the proposed studies will provide important information on the role of diet in brain and cognitive health in middle-aged subjects, which will provide important nutritional implications for healthy aging promotion and AD prevention.